Laminar-turbulent coexistence in annular Couette flow

Abstract

Annular Couette flow is the flow between two coaxial cylinders driven by the axial translation of the inner cylinder. It is investigated using direct numerical simulation in long domains, with an emphasis on the laminar-turbulent coexistence regime found for marginally low values of the Reynolds number. Three distinct flow regimes are demonstrated as the radius ratio $\eta$ is decreased from 0.8 to 0.5 and finally to 0.1. The high-$\eta$ regime features helically-shaped turbulent patches coexisting with laminar flow, as in planar shear flows. The moderate-$\eta$ regime does not feature any marked laminar-turbulent coexistence. In an effort to discard confinement effects, proper patterning is however recovered by artificially extending the azimuthal span beyond 2$\pi$. Eventually, the low-$\eta$ regime features localised turbulent structures different from the puffs commonly encountered in transitional pipe flow. In this new coexistence regime, turbulent fluctuations are surprisingly short-ranged. Implications are discussed in terms of phase transition and critical scaling.

arXiv comment24 pages, 17 figures

References in corpus (8)

• Computational Study of Turbulent-Laminar Patterns in Couette Flow
• "Barber pole turbulence" in large aspect ratio Taylor-Couette flow
• The rise of fully turbulent flow
• A Universal Transition to Turbulence in Channel Flow
• Mean flow of turbulent-laminar patterns in plane Couette flow
• Universal continuous transition to turbulence in a planar shear flow
• Experimental investigation of laminar turbulent intermittency in pipe flow
• Turbulent bifurcations in intermittent shear flows: from puffs to oblique stripes

Cited by in corpus (1)

• Flow Statistics in the Transitional Regime of Plane Channel Flow